3-(Methylthio)thiophene is used in the electronic industry, e.g., 3-(Methylthio)thiophene can be used as intermediate for the synthesis of API (see for example WO2005040110). It is also used for yielding oligothiophene (J. Org. Chem. 1996, 61, 8285 and ref herein), oligomers that have attracted great attention for their chemical stability, ease of fictionalization, and variety of useful properties.
The synthesis of this compound has already been described (see for example, Tetrahedron Letters 1994, Vol. 35, No. 22, pp. 3673-3674 and WO 2005/040110). When tetrahydrofuran (“THF”) is used as the solvent, the described process usually involves the mixing of 3-bromothiophene and butyl lithium at −40° C. in hexane. THF is added to allow the formation of 3-lithiothiophene via metal halogen exchange that yields 3-lithio thiophene at −40° C., followed by a reaction between 3-lithiothiophene and an electrophile at room temperature, e.g., about 20° C., Subsequently, dimethyl disulfide is added to obtain 3-(methylthio)thiophene, e.g., in 71% yield.
However, exothermicity that is inappropriate for most commercial applications is observed at −40° C. (+9° C. with a dry ice bath at −40° C.) upon the addition of THF.
Thus, there is a need for commercially suitable processes for production of 3-(methylthio)thiophene.